Recent groundbreaking advances in scanning probe lithography made by the Mirkin Group, headed by Dr. Chad A. Mirkin, at Northwestern University have addressed many technical limitations of conventional nano-patterning strategies using innovative methodologies for controlling molecular and material architecture at the nanoscale and microscale, i.e., between 1 nm-10 μm length.
In a technically significant departure from the conventionally used cantilever-based paradigm, Dr. Mirkin invented Cantilever-Free Scanning Probe Lithography (CF-SPL), a technique that relies on a new architecture in which the cantilever is replaced with an inexpensive elastomeric film containing up to millions of pyramidal tips on a rigid substrate and affording massive scaling while preserving high resolution.
As recognized by Dr. Mirkin, massively parallel tip arrays can be used for direct molecular printing—a technique known as Polymer Pen Lithography (PPL) or diffraction-unlimited patterning with light when combined with near- and far-field photolithography—a method known as Beam Pen Lithography (BPL).
To produce uniform feature sizes over large areas with either PPL or BPL, the probe array must be aligned parallel to the substrate. Conventionally, this procedure is performed manually, by optically inspecting each corner of a probe array and identifying the points-of-contact or automatically by measuring force resulting from a physical contact between a probe array and a substrate.